Oxide terminal



`Marsh 2 1926- A. n D. KEENE OXIDE TERMINAL Filed Oct. l5. 1925 /ff f/ /f/ /r/ /1 WITNESSES:

ATTORNEY Patented Mar. 2, 1926.

UNITED STATES PATENT OFFICE.

ALVIN' 1 KEENE, OE PITTSBURGH, PENNSYLVANIA, AASSIGNOIR, TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

OXIDE TERMINAL.

Application mea october 15, 1923. serial No. 668,500.

To all whom 'it may concern.

Be it known that I, ALVIN D. KEENE, a citizend of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Oxide Terminals, of which the following is a specification.

My invention relates to electric furnaces and particularly to terminal members for electric resistance furnaces.

One object of my invention is to provide a relatively simple and easily installed terminal member for -an electric furnace of the metallic resistor type.

Another object of my invention is to provide a terminal member for -metallic resistor furnaces that shall be easily and quickly connected to the ends of the resistor and that shall provide a joint having a relatively low resistance.

Another object of my invention is to provide a terminal member for metallic resistor furnaces that shall require only the simplest tools to install.

In practicing my invention, I provide a terminal rod, of relatively large diameter and of a non-oxidizable material, extending. through the refractory walls of afurnace structure and connected to the end ofthe metallic resistor member. The inner end of the rod is provided with an opening within which is placed a metallic member that changes its crystalline structure and swells or expands upon being subjected to a relatively high temperature. The end of the` resistor member, of substantially non-'oxidizable ltterial, is inserted in the opening in the end of the terminal rod and is tightly gripped or wedged therein after the first operation of the furnace. l

In a modified form of device embodying my invention, ,a tubular rod is employed instead of a solid rod. In a further modiication, an intermediate metal member may be em loyed to connect the co-operating ends of) the terminal rod and of the resistor member.

In the drawings, t Figure 1 is a view, in vertical longitudinal section, of an electrical resistor furnace embodying my invention,

. Fig. 2 is a view partially in side elevation and partially in longitudinal section. of a Fig. 4 is a fragmentary view, in longi- -tudinal section, of a still further modication of a device embodying my invention.

An electric resistance furnace l11 com prises an outer casing 12 of a suitable heatinsulating refractory material and an inner lining 13 of a suitable high-temperature resisting refractory material. The inner lining 13 and the casing 12 therefor, may be built up of a plastic mass or of bricks or blocks andi enclose a furnace chamber 14 of any suitable or desired contour and dimensions.

A relatively heavy resistor member 16, preformed to. comprise a plurality of straight and substantially parallcl-extending convolutions is located within the chamber 14 and comprises a material that is substantially non-oxidizable, such as nichrome. Any suitable or desired means of supporting the resistor 16 may be employed and the means here shown are a plurality of spaced refractory rods 17 that secure the resistor member against the cooperating wall of the furnace chamber. As the method of supporting vthe resistor forms no part of myinvention, it is not further illustrated or described.

A terminal member for the resistor memvided to more effectively insulate the ter-V minal rod 18 from the refractory lining 13 and the casing 12.

At its inner end, the rod 18 is provided with an axial opening 22 extending into the rod for a short distance and a sleeve 28 of steel or` cast iron'is located within the opening 22. The sleeve 28 has an inner opening of substantially -the same diameter as the resistor rod 16, one end of which is located within the sleeve 23 and is. initially held therein by a set screw 24. The sleeve 23 undergoes a change of crystalline structure upon being subjected to the relatively small amount of high temperature at which a furnace of this type operates, and swells, thereby tightly wedging the non-oxidizable resistor member 16 within the equally non-oxidizable terminal rod 18. The sleeve '23 is also oxidized upon being subjected to the relatively high temperature, thereby causing -a still further swelling or expansion of the sleeve, anda tight gripping or wedging of the resistor rod 16 within the opening 22. The oxidizing sleeve 23 becomes even more highly conducting than it was originally, thereby providing a joint of relatively very low resistance.

Any suitable or desired means'for holding the rod 18 in its proper operative position relatively to the refractory wall may be employed, and I have here Ishown an inner nut 25 and an outer nut 26, together with a washer 27 located against the outer surface of the outer casing 12. A terminal lug 28 of usual construction may be provided to which the end of a supply circuit conductor (not shown) maybe sweated, and eXtra nut 26 is provided to securely clamp the 'lug 28 on the rod 18.

Instead of the rod 18, I may employ a tubular member 29 illustrated in Fig. 4, within the inner end of which a sleeve 23 of steel or cast iron is located substantially as hereinbefore described in Vconnection with the rod 18. Substantially the same means for holding the tubular rod 29 may be em ployed, as were hereinbefore described for the rod 18.

In a still further modification, I may employ a `rod 18 in combination with an intermediate `member 31, of substantially nonbxidizable material, such as nichrome, that is provided with two axial and alined openings 22 and 32, to receive respectively the endsof the resistor member 16 and f the rod 18, sleeves 23 and 33 of oxidizable material being inter osed between the ends of the resistor memiier 16 and of the rod 18 and the member 31.

If a plurality of relatively short resistor members 16 are to be connected in series circuit relation to each other, connectors 34 of the type disclosed and claimed in my copending application, Serial No. 649,781 iled July 6, 1923, and assigned to the lVestinghouse Electric & Manufacturing Company, may be employed.

The operation of the sleeve 23'is more particularly described in the above-mentioned application, towhich reference may be had for further details of operation thereof and particularly those ,of the connectors 34.

I have illustrated terminal rods, either solid or tubular, of relativelyl large crosssectional area as compared to the resistor wire, thus insuring that only a relatively eats generated in the vthat is operative at terminal rod where it is located in and extends through the refractory Walls, thereby insuring a minimum amount of heat loss during the actual operation of the furnace.

Various modifications and changes may be made without departing from the spirit and scope of the invention, I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art or are set forth in the appended claims.

I claim as my invention:

1. A terminal structure for a resistor member, comprising a terminal member, of larger cross-sectional area than said resistor momber operatively engaging the same, and

means in said terminal' member that is operative at a high temperature to swell `and tightl grip the resistor member.

2. X terminal member for a resistor member, comprising an elongated metal portion having an axial opening at one end thereof, and a sleeve'itting in said opening and operatively engaging the end of said resistor member, said sleeve swelling upon being subjected to a relatively high temperature and wedging saidgresistor in said opening.

3. A terminal member for a resistor member, comprising an elongated member of larger cross-sectional area than said resistor member and intertting therewith, and a metal member, interposed between said elongated member and said resistor member,

' the operating temperature of said furnace to swell and tightly wedge said resistor member in said elongated member.

4. A terminal structure for a resistor member, comprising an elongated metal terminal member 1nterfitting with said resistor member, and a metal member operatively engaging saidresistor and said terminal member, said metal member swelling upon being subjected to a relatively high temperature and tightly wedging said resistor member in said elongated terminal member.

5. A terminal structure for a resistor member of non-oxidizable material, comprising a terminal member of non-oxidizable material and of larger cross-sectional area than l between said terfeetive to change its granular structure and oxidize upon being subjected to a high temperature whereby it swells and Wedges said resistor member in said terminal member.

7 f A terminal structure for a resistor member, located in a casing, comprising an elongated terminal member, of substantially non-oxidizable metal extending through a wall of' the casing and having an opening in its inner end for interftting with one end of the resistor member, means for maintaining it in position in the wall, and a metal member inside of said terminal and operatively engaging said resistor and swelling upon the application of heat thereto whereby it wedges the end of the resistor member in said terminal member.

In testimony whereof I have hereunto subscribed my name this 9th day of October, 1923.

ALVIN D. KEENE. 

